I can give a real example of this that happened to me. I have a Steam account. Many years ago I created it using a Hotmail email account. I never used Steam for a couple of years. One day last fall I decided I wanted to do a little gaming, but I could not remember my account. I did the password reset but it never came through. I tried logging into my old Hotmail account, but they said it didn't exist. I re-created it, resubmitted the Steam password recovery form, and recovered my account _with_ saved credit card information.